Lawrence Slobodkin starts with an introduction where he explains the idea
behind the book, as well as some basic concepts. Thus, when talking about
the idea of ecology, he
emphasizes the importance of change:
The practical problems of ecology are all concerned with changes.
Earthquakes, moving glaciers, years of drought and years of flood, volcanoes,
and building projects all cause ecological changes. Sometimes new kinds of
organisms burst onto the world scene and make major changes. Even in the
absence of human disturbance, the world goes through changes of many kinds
and on many scales. The practical concern with ecology is based on the
real possibility that we are disturbing the world in dangerous ways and that
our understanding and knowledge are so inadequate that we can cause
irreparable damage without even noticing until it is too late.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 5)
Slobodkin, therefore, is no dogmatic conservationist. He seems to understand that there is no
nature without change. Ecology is a process, and it is not always easy to
figure out the ultimate consequences of a given event:
One change initiated by the US Forest Service in the early twentieth century was to fight the
occurrence of wildfires.
This was successful enough that undergrowth and dead wood became thick on the
floor of western forests.
In 1987 a wildfire of singular intensity, with the capacity to leap over
roads and firebreaks, appeared in Yellowstone Parl, scorching at least 20 percent of the
park. The land looked dead. Almost immediately a book appeared proclaiming
"the end of nature." [Slobodkin is referring to Bill McKibben's The End of Nature] To claim nature has "died"
is silly and nonproductive, even if it sells books. Nature changes. It
cannot pass away.
In 2000, another drought year, once again uncontrollable wildfires struck
Yellowstone. The are of the forest that had been spared in 1987 now was
burning. I was in Yellowstone Park during the fire and saw that the formerly
burned-over sections were a green tree nursery of small lodgepole pines, unburned by the new fires.
Fires had happened before and will happen again, and the forests of
Yellowstone Park will certainly change as a result of those fires, but the
changes will not by any means be catastrophic. There will still be forests
in Yellowstone Park. In fact, the cones of several of the trees of
Yellowstone release their seeds only if they are baked in a fire.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, pp. 10-11)
It quickly becomes clear, then, that Slobodkin is not your usual ecologist or
environmentalist. He seems to consider ecology quite important (perhaps
even central) to our future, but that does not make him a raving lunatic
spreading news of the end of the world. His approach is slightly
different, which is quite refreshing:
Concern with ecology is necessary. It is not a fad. We can and do change
the properties of nature, although the mechanisms of ecology do not
change, just as the laws of chemistry and physics do not change.
Nature is neither wise
nor benign nor malicious. There are no immaterial forces guiding ecological
systems, although these are sometimes suggested. Solving practical
problems of ecology requires using science and technology in a political,
social, and even religious context.
We are, directly or indirectly, actors in nature. Its rules limit us and
its dangers challenge us. If ecologists are very successful, they will help
maintain the pleasant and livable properties of the world. If not, the world
will change in unpleasant ways.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 11)
That approach contrasts with what we see in the majority of cases:
Ecology is in danger of becoming an uncomfortable blend of a science and
a passé but still trendy mass movement. Nevertheless, the
residual enthusiasts for ecology have a copious supply of study material
available. We are bombarded by magazines, news reports, and enough television
specials to make even the most beautiful landscape trite. Small bookstores
have a section on ecology or environmental crisis just after cook-books and
before the economics section. Most of the popular ecology books are
designed to encourage depression or alarm. Bleak predictions of disaster
provide pleasurable frissons, once supplied by such ideas as an invasion from
Mars and infant damnation. Literally hundreds of books dealing with
environmental and ecological problems will appear this year. A few of these
will be picture books of remarkable beauty.
But beauty does not sell books fast enough. Therefore, these lovely picture
books will probably include a proviso that they are accounts of endangered
islands in a sea of advancing environmental degradation.
Most books about ecology are listed as nonfiction, which is not
necessarily the same as being demonstrably true. There is also
ecological fiction, in the same sense as detective fiction and science
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 13)
As the author explains in the introduction, he is convinced that it is
possible (indeed, necessary) for regular citizens to learn the basic ideas
of ecology, which is why he embarked on this project. And he does so
without forgetting his roots as a scientist. For example, he explains how
he introduced his college students to the ecological framework of mind:
The students were then asked to insert knitting needles in the ground and
see how many newly shed leaves the needles picked up. From this they could
determine, if it was late in the fall and the trees above were almost bare,
how many layers of leaves there were when the leaves were still on the trees.
This way of measuring the number of leaf layers that were on the trees by
determining the layers on the ground has obvious weaknesses related to
drifting of leaves and sampling, but, except for leaves too small to pierce
with a needle, is independent of leaf size.
Part of the exercise is for the students to consider what can be learned
from available information. To what questions might all our numbers be
an answer? Why are there almost no intact leaves and also no ribs of
completely eaten leaves? Why is the number of leaf layers in our forest
always around six? Why isn't it one? Why isn't it twenty? Why isn't there
a deep layer of this year's and previous years' leaves lying in the ground?
I could have told them the purpose of the exercises. I did not. I wanted
them to learn where scientific questions come from. It worked for some of
Each student was then required to collect fallen leaves to identify the
kinds of trees there were in the forest. With around ten leaves per student,
the exercises required only nine thousand dead leaves. Anyone who has raked
a backyard will realize that nine thousand leaves will not materially lessen
the litter cover of a woodlot.
Is this experience equivalent to a camping trip with Thoreau? Certainly not, but it still
permits firsthand understanding of some ecological processes. We had
demonstrated that close observation of small things can open intellectual
windows with wide views.
The fact that essentially every leaf collected had been eaten in part suggests
that all of the leaves were edible to some organisms during at least part of
their lives. The fact that almost none of the leaves were eaten down to the
stems and veins implied that something stopped the consumption process before
it was complete. This might conceivably be that the leaves had rapidly
"ripened" in some sense so as to become inedible soon after the herbivores
took their first bite. Another possibility is that the meals of the
herbivores were interrupted by the animals being attacked by carnivores before
they could finish eating.
The fact that the campus forest was green until the leaves were changed by
the onset of fall therefore could be taken to imply that the herbivore
population feeding on them was in fact kept low by predators.
From the fact that there was no more than three years of leaf fall on the
ground, we could infer that the detritovores —the fungi, worms, wood
lice, and so on— were finishing up all their potential food and were
therefore not prevented by predators from growing up to their food supply.
Observations similar to these are extremely common, implying that there are
discernible regularities in ecological systems in nature. More specifically,
there is an inference that the food energy supply is limiting to the total
nonphotosynthetic part of natural communities.
Scientific argument does not rival the charm of a coral reef, but I think
it is intellectually beautiful that at least someties the complex ecological
world permits itself to be understood by a suitable combination of simple
observation and thought.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, pp. 28-29)
That is Slobodkin's appealing approach to the topic at hand, a mixture of
scientific methodology and passion.
Before we look at any specific ecological systems it will help to
understand two fundamental facts that are basic for understanding everything
else. These are:
- Water is enormously important for all life and is an extremely peculiar
- Organisms are local accumulations of energy. Energy is crucially
important for all organisms.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 33)
Animals can obtain energy only by eating it. Green plants and colored
bacteria perform photosynthesis, which lets them bind the energy in
light into energy-rich molecules. These molecules can be taken apart by
the plants themselves or by animals that eat them, releasing the energy for
work and growth.
In respiration carbon
dioxide is given off and oxygen is taken in. Respiration and photosynthesis
are mirror images of each other. It takes exactly as much oxygen to consume
a carbohydrate molecule as was produced by the photosynthetic process that
The rate at which energy is taken in by an organism is usually not equal to
the rate at which it is used. A heavy meal increases our store of energy,
and a session of strenuous exercise or a long fast decreases it.
For most animals there will be times when food is abundant and times when it
is absent. The food, or at least the energy from the food, must be stored
during the rich food season to be used when food is absent. Many animals
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 37)
The fact that tiny changes can have a major impact because their effects
are multiplied by circumstances and events is one of the most intriguing and
frightening aspects of ecology. Assessing the effects of prospective
changes is the focus of a large proportion of ecological disputes.
Change in the concentration of atmospheric carbon dioxide seems a small
problem when compared with some changes that have been brought about by
organisms. One of the greatest changes organisms have brought about in the
earth's atmosphere is the oxygen-rich atmosphere. Approximately 20
percent of the air is oxygen. If life had not appeared, there would be almost
no atmospheric oxygen.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 43)
The fact that photosynthesis produces oxygen does not explain the 20 percent
concentration of oxygen in the atmosphere. Photosynthesis is the precise
mirror image of respiration. Where photosynthesis uses carbon dioxide,
captures energy, and produces oxygen, respiration uses oxygen, releases
energy, and produces carbon dioxide. Essentially all the photosynthetic
products are respired away.
Plants respire around a third of the energy they fix in photosynthesis for
their own use. Herbivores eat a large share of living leaves. Almost all
organic material that falls to the ground, as dead leaves and wood, is eaten
by decomposers —bacteria and molds. Some organic
material may be consumed by wildfires. In these processes essentially all of the oxygen produced by
photosynthesis is recombied with carbon to produce carbon dioxide. Where
did the atmospheric oxygen come from? Thinking of it in a slightly different
way: If respiration and fire are the precise reverse of photosynthesis and if
all organisms, plants and animals, use respiration, why was any oxygen left
over to help form the atmosphere?
Part of the explanation is the important concept that things in nature
never come out quite even unless there is some mechanism that forces them
to. Over global space and geologic time very slight failures to come
out even result in massive accumulations or eliminations.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 47)
Over billions of years rainwater and river water have drained into the oceans and ultimately evaporated
to fall as rain once more —an endless cycle of water. The early oceans
were much less salty. If we boil water in a teakettle, a visible crust
of minerals soon forms inside the kettle. The boiling water that evaporates
leaves its dissolved minerals behind, so that the salt content of the oceans
has been gradually increasing for the last four and a half billion years.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 73)
Upwelling regions, along with estuaries and regions that receive drainage
from the continents, are the source of more than 90 percent of the world's
supply of edible fish. When the water leaves the continent and flows
out into the ocean it enters a condition similar to that of summer stagnation
in lakes, in which light is present but nutrients are diminishing, to be
replenished from deep, dark waters in upwelling regions. The time between
sinking and upwelling for any single water molecule may be thousands of years.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, pp. 79-80)
Protecting plants from parasites occasionally has unpleasant side effects. For years extremely
toxic chemicals were added to the soil on eastern Long Island to protect potato plants from the golden eel worm, a
little nematode that infects their roots. This poisoned local wells. The
present solution is to drink bottled water and to switch from growing potatoes
to growing grapes, which are afflicted with an entirely different selection of
pests and parasites, requiring quite different poisons to control them.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 87)
Underemphasized in this pictures is that lakes take in a great deal of
material from their watershed —leaves, pieces of wood, and a miscellany
of organic garbage. This exogenous material may be eaten by bacteria,
which are in turn prey for microzoo-plankton, which feed larger zooplankton,
which in turn feed fish.
In fact there are two more or less distinct food webs in each lake. One is based on bacteria, whose
energy supply comes largely from material washed in from the watershed. The
other is based on phytoplankton grown in the lake from recycled mineral nutrients; their energy
supply is the photosynthesis occurring in the lake itself.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 96)
The watershed for a pond may be a single valley, but the watershed for the
ocean is all the land on earth. All the rocks of all the continents are
washed in water heading for the ocean. This drainage is where nutrients
come from, balancing the loss to the deep sea from the sinking of detritus.
At first glance this seems unreasonable. Why hasn't the land been exhausted
of its nutrients in the last few billion years? It would have been, except
for the fact that many of the rocks and mountains on land were originally
formed under the sea. They are made up of the nutrient-rich sedimentary
detritus that succeeded in sinking to the bottom and has accumulated over
millions of years. This sounds like wild speculation, but it is much more
certain than most supposed scientific facts, because we can find the fossils
of deep ocean animals in the rocks of high mountains.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 98)
Let humanity do its worst! Rain will still fall, rivers will still flow,
and there will still be storms and floods and droughts. There will still be
photosynthetic organisms pumping out oxygen, and nonphotosynthetic organisms
using it and burning the products of photosynthesis. However, there is no
certainty that any particular species or landscape will survive. The problems
for humans are in the details. Will our particular species survive?
Some global properties involve relatively small quantities of matter
—thousands of tons rather than millions. People can affect these,
and they can change rapidly over periods of tens, hundreds, and thousands
of years rather than thousands of millenia. The quality of air and of river
water and the chances for survival of some landscapes and of many species,
including our own, are in our hands.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 99)
We may want to destroy or reduce a population that is declared a pest or a
danger. In that case the attack should focus on the organisms of highest
reproductive value. For example, it has long been known that the number of
rats in a modern city
approximates the number of humans, and if public sanitation deteriorates,
the rats can outnumber the humans.
Rats are usually attacked by placing poison baits and traps in places rats
pass. This procedure selectively destroys itinerant males. The animals of
highest reproductive value —the nesting mothers— may not be
damaged, nor is their care of the young disturbed by excess attention from
males. The effect of this sort of policy is that large numbers of rats can
be caught and displayed, demonstrating that the eradication company is doing
its job, but the reduction per dollar in the rat population is minimal,
ensuring that the eradication company and the rats both can continue.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 126)
Extinction is generally a bad thing, but that assertion requires defense.
Who wants mosquitoes?
There are five basic reasons to preserve species and populations from
extinction. I will present them in order of what I consider descending
significance. This is my personal order. Different ordering is possible.
First, I see each kind of organism as a masterpiece left to us from the
past. Every species on earth has literally billions of years history behind
it. Its ancestors lived through one crisis after another, day by day,
year by year, and millenium by millenium. They have effectively taken
advantage of all the good times and somehow survived the bad. They have
changed in response to some pressures, hidden from others. I believe that
it is horrible that the history of any species should be brought to an end
by shortsighted or careless human activity or inactivity in my lifetime.
This is my personal belief. I hope others agree with me.
The second reason is a more practical one. There is much to be learned
by careful study of any species, and so few species have been carefully
studied that the extinction of a species, particularly an unstudied species,
is intellectually equivalent to burning a book before it has ever been
read. There is no guarantee as to what would be learned by the study,
but the world would be a poorer place if the species were not there to be
The third reason is that wild organisms of many kinds produce saleable
commodities. On a very practical level species extinction is generally
bad for medicine and for other business. The spectrum of herbal medicines in the health food
shop of your local mall will demonstrate how many and how curious are the
virtues attributed to relatively rare plants. Sometimes these are used without
proper clinical testing, but their role in folk medicine is of sufficiently
long standing that proper testing ought to be done and the plants ought to be
around for that purpose if no other.
A fourth argument is that different people use a broad diversity of
species, some of which are relatively rare and not subject to cultivation.
The field of ethnobotany
is now cataloguing these organisms and their uses. Survival of these species
may aid the cultural survival of the people that use them.
The fifth reason that has been proposed in favor of species preservation
and biodiversity I
find ingenious and fascinating but transparently specious and therefore
dangerous both to the future of ecology and the future of the natural world,
which we have accepted as our object of study. This is the "rivet in the
airplane" argument. It is a story that begins with elementary fact, then
blossoms into a full-fledged parable and emerges with a reification, a
creation of a mythical reality.
First facts: It is a fact that natural communities have ten to ten thousand
species in them. (That is, there are from ten to ten thousand species that
can be retrieved from exhaustive sampling of a reasonably small area.) If a
particular species is found in a community, it obviously has some role in the
community. Should that species be eliminated, whatever the role of that
species had been, it is no longer precisely filled, although various
competitors can and do take over parts of the role.
Now the parable. Consider an ecological community as an airplane. An
airplane has many interacting parts. Imagine a passenger who finds that one
screw in the cabin is loose and removes it. It will probably make no
difference. But now someone else comes by, finds another loose screw, and
pockets it. While a fair numberof screws can be removed without evident
harm, if a sufficient number of screws have been removed, the removal of one
more screw will result in the plane crashing.
In the same way, states the parable, removal of one species from a forest may
do no visible harm, but if enough species have been removed, the loss of one
more population results in collapse of the forest community.
This is a beautiful and vivid image. The parable asserts that loss or
addition of critical species will send reverberating waves of change through
a community. Sometimes this appears to be valid. Is it universally true?
In what sense is there really an airplane?
What usually happens when a species is eliminated from some region? Its
parasites will also be eliminated. Its predators will be hungrier. Its prey
will perhaps become more abundant, and in some cases there may be other
effects. Grass may grow taller, sheltering more mice, or some tree may be
unable to germinate its seed.
We do know that losing a particular species from an ecosystem or adding a
new species may have consequences for other species. For example, loss
of elephants or alligators would be expected to seriously alter the world for
other plants and animals —elephants rip up or knock down trees,
warthogs feed among the newly exposed roots, and baboons lift the loose
rocks in the exposed soil for scorpions and other tidbits. Alligators in the
Florida Everglades dig holes that retain water even when rain is sparse, and tufts of willow
trees and other vegetation come to surround these alligator holes. Similarly,
beaver dams transform streams into marshes and thereby provide habitats for
To eliminate elephants or alligators or beavers would radically alter the
ecosystems. But such large effects are perhaps less interesting than more
subtle and specific effects that are harder to see. Termites in East Africa
build mounds up to six meters high that are islands on the flat plains. This
permits some plants to escape the annual fires that sweep the low grasslands.
Don't these examples simply confirm the rivet analogy? Not really. Each
example relates to a few specific species. The rivet analogy makes two
assumptions: first, that there is no way of telling which rivets are important,
and second, that there is an airplane. But there is no airplane! There
may be a pile of parts, each one closely connected to a few others, and each
pile only loosely connected to several other piles, but general collapse does
not occur. I am not even certain what general collapse would look like.
Although the elimination of one species may not always result in a wave of
other disappearances, some species are certainly more critical than others.
Also, although I oppose unfortunate metaphors, which I believe are damaging
to science itself, I believe most strongly that the actual global extinction
of any species is a real and irremediable lessening of the richness of the
world. Our avoiding species extinction is tantamount to passing masterpieces
on to coming generations.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, pp. 139-144)
Recently it has been shown that some species that meet the definition of
have settled into their new home and now have a broad range of ecological
connections, such as might be expected of a long-term resident. Attempts
to extirpate them may prove more dangerous to other resident species than
leaving them alone.
It is difficult to close borders against exotic fruits, vegetables, and
insects, no matter how dedicated the border guards. I believe that
ultimately the fight against invasive species, despite enormous effort and
flood of scientific papers, will end in defeat. How much will it matter?
There will be changes —cases of native populations being extinguished,
plant cover changing over large areas, diseases breaking out in new places.
Some agricultural practices will change, but the likelihood of large-scale
disaster is low, and in any case not much can be done to prevent the
There is a nightmare image of the world filling completely with dandelions,
kudzu, and rabbits. It isn't realistic, and it will not happen. Rosenzweig
suggests: "The breakdown of isolating barriers between biogeographical
provinces will not have much effect on species diversity. In the short term,
it will reduce global diversity but increase local diversity... The
considerable damnage [some] exotic species have been known to do comes
primarily from direct effects of particular introductions."
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, pp. 151-152)
Simplistic proposals have been made to grow more forests and thereby
remove carbon from the air. Aside from issues of where these forests are
to be grown and who is to do the work, this scheme will not work for
elementary biological reasons.
When a tree is growing it is in fact taking carbon out of the air, but
once the tree reaches its full size its respiration returns as much carbon
to the air as its photosynthetic activity removes. When it dies and the
wood rots or is burned, all the sequestered carbon is returned to the air.
The net change in atmospheric carbon dioxide produced by any tree in a
forest from its birth to its disappearance is zero. Planting a forest
of young trees will temporarily remove some carbon dioxide from the air, but
only until the forest becomes mature and stops increasing in total wood
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 163)
"Naturalness" also may carry the connotation of freedom from additives of all kinds. The use of
additives in food is another place where ecological and medical considerations
interact. Preservatives are useful precisely because they are poisonous to
molds and bacteria. While we are biochemically different from molds and
bacteria, all organisms are similar enough so that something that kills a
bacterium is probably not the best thing for me, unless the bacterium itself
is an even greater immediate danger.
Most foods may taste best when fresh, but some preservatives may enhance the
flavor of foods while they ensure long shelf life. Salt meats and sausages,
herrings, anchovies, sauerkrauts, and pickles owe much of their flavor to the
salt that probably was first added as a preservative.
What are less defensible are some of the multisyllabic small-type dyes and
other additives that are listed on the wrappings of ready-to-eat cereals,
candy bars, breads, and other foods that are usually given to children. On
the other hand, complete absence of these mystery additives may perhaps
increase the average price of food and perhaps lower its quality.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 191)
There is great concern that these genetically engineered seeds may have
dangerous ecological properties that we cannot anticipate and that these
consequences may set up problems more difficult and more expensive to solve
than the initial problems of insect damage.
For example, what if a gene for immunity to insects is transmitted to pest
plants? While we do not expect genes in corn to make their way into other
species very often, examples of this type of genetic tranmission are known.
What if desirable species of insects are severely damaged by consuming
engineered plants? How would this affect pollination of crops such as clover
or of wildflowers?
The primary novelty of genetic engineering is that it can produce more rapid and more curious
genetic modifications than could be produced by selecting genetic variants.
Genes with specific properties can, in a sense, be injected directly into a
genotype. I don't believe that the possible dangers of this process have yet
been completely analyzed.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 194)
How we argue about ecology is often as important as the substance of our
arguments. There is a temptation to focus on winning the argument. The
issues of ecology are too important for that. If you happen to win an
important argument by using what you know to be bad science, in the long run
you will have damaged the future of science itself. You will have destroyed
the authority of good science, and on some future occasion opponents may use
equally specious science to destroy your position. There is a danger that
using bad science to effectively win arguments will cost us one of our
only sources of clear truths.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 209)
To assign moral purpose to natural events is not helpful for management.
The moral implications of management procedures are our problem, not
nature's. We must guard and even construct the properties of our own
world to meet our needs, desires, and moral concerns. We are the only
organisms capable of this in any serious way.
(Lawrence B. Slobodkin: A Citizen's Guide to Ecology, p. 211)
Entertainment Factor: 5/10
Intellectual Factor: 5/10